More than 50 inmates reportedly took over part of HMP Northumberland in Acklington overnight. There were no reports of injuries, but officers at the prison confirmed a "disturbance" had taken place over several hours.
A spokesman for Sodexo, which has managed the prison since December, said: "We can confirm there was a disturbance at HMP Northumberland.
"It was confined to part of one wing of the prison and has now been resolved. We will carry out an investigation into this incident."